In the ISI-dominant regime, we consider a scenario with four targets located at the same velocity (20 m/s), but with different ranges, as shown in Fig. REF  (left). As shown in Fig. REF  (right), the standard FFT processing [1]}, [2]} or the existing OTFS detectors [3]}, [4]}, [5]} can detect at most two targets as Target 3 and Target 4 fall into the same range-velocity bin as Target 1 and Target 2, respectively.
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